As C-T, I think the planners had a lot of land to play with and possibly had a guideline in the Nottm Corporation Architects office maybe along the lines of , If a new estate road serves over xxx houses then it has to be a certain corridor / road width, for the pleasing effect and possible expansion.
Looking at the map below, the Bulwell end does sort of line up with Highbury Estate.
If it had maybe intended to go that route, although it looks a mess crossing 3 rail lines it's not quite as complicated as it seems as one rail line is below the road level, one is above the road